Processing messages for an application running on a computer external to a communications management unit (CMU)

ABSTRACT

A method for processing Aircraft Communications Addressing and Reporting System (ACARS) messages at a Communications Management Unit (CMU) on an aircraft is provided. The method includes, for an ACARS downlink message, receiving a message at the CMU from an application on a computer external to the CMU onboard the aircraft, reading a field in the message that indicates a message type for that application, determining an ACARS label associated with the message type, using the determined ACARS label instead of the industry standard ACARS label/sublabel associated with the onboard application external to the CMU, and sending the ACARS downlink message encoded with the determined ACARS label to a ground system to be delivered to a peer ground application.

BACKGROUND

Many Aircraft include a Communication Management Unit (CMU) or aCommunication Management Function (CMF). For simplicity, thisspecification will use the term CMU as generic for both CMU and CMF. Inexisting systems, the CMU includes a configurable Aircraft OperationsCommunication (AOC) application. Those skilled in the art also use theacronym AOC to indicate Airline Operations Control. The configurable AOCallows the operator to customize many features of the AOC; such asformat messages; determine whether to display the message on a display;customize the display of messages on a display; determine when to send amessage (e.g., automatically send or send upon receiving input from apilot or other user); determine what data, if any, available in the CMUshould be incorporated into the message. Other configurable functionsare available in the AOC as is known to one skilled in the art.

The operator defines the configurable AOC application within the CMUwith a loadable file such as an Aircraft Operations Communication (AOC)database (DB), Airline Modifiable Information (AMI), or the like. Forsimplicity, this specification will use the term AOC as generic for bothAOC and AMI databases. The AOC database includes information used toselect the various configurable options within the AOC such as:formatting and display of various uplink messages; formatting anddisplay of various downlink message; the display of the pages and logicused to create the downlink messages; formats for printing uplinkmessages; and/or the logic behind the messages and display/HMIfunctions. Other information is included in the AOC database as is knownto one skilled in the art.

In addition to the CMU, other computers are located on-board theaircraft. For example, electronic flight bags (EFBs) may be used forsome cockpit operations. An EFB may be brought onto the aircraft by apilot or other crew member or the EFB may already be installed in theaircraft. In the past, EFBs were portable or fixed personal computers(PC). Now EFBs are personal devices, such as iPads or other types ofpersonal tablets. Other computers on-board the aircraft include linereplaceable units (LRUs), maintenance terminals, PADs, personal devicesand other cabin terminals.

Traditionally, messages are communicated between applications running onthe CMU and ground systems associated with the airline operating theaircraft. These messages typically include a label that depends on thespecific application that generated the message. When received at theground system, the label of the message is used by the operator to routethe message to the appropriate ground application. Messages thatoriginate from applications running on other computers on the aircraftuse the label/sublabel (rather than label) in a different way. For thesemessages, the label/sublabel is used to indicate the computer or linereplaceable (LRU), rather than the application, that originated themessage.

As operators continue to modernize their fleets, there is a trend tomove applications traditionally run on the CMU to other computers on theaircraft. Due to the size of these fleets, not all aircraft are upgradedat the same time. While these modernization efforts are in process,messages from the same application on different aircraft would need tobe handled differently by the operator's ground-based systems. Inaircraft that have been updated (e.g., applications have been moved toother computers on the aircraft), the traditional label could not beused by the ground system (e.g., ground stations, datalink serviceprovider and operations center that hosts the ground applications) toroute the message to the correct ground application. Rather thanindicating the type of message, the label/sublabel indicate the computeron the aircraft that generated the message. To properly handle messagesreceived at the ground system, the operator would need to know whichconfiguration was used by the aircraft that generated the message andthe message type so that the message could be routed to the appropriateground application.

For the reasons stated above and for other reasons stated below whichwill become apparent to those skilled in the art upon reading andunderstanding the specification, there is a need in the art for aprocess for handling messages for AOC applications that is independentof the computer running the AOC application on the aircraft.

SUMMARY

A method for processing Aircraft Communications Addressing and ReportingSystem (ACARS) messages at a Communications Management Unit (CMU) on anaircraft is provided. The method includes, for an ACARS downlinkmessage, receiving a message at the CMU from an application on acomputer external to the CMU onboard the aircraft, reading a field inthe message that indicates a message type for that application,determining an ACARS label associated with the message type, using thedetermined ACARS label instead of the industry standard ACARSlabel/sublabel associated with the onboard application external to theCMU, and sending the ACARS downlink message encoded with the determinedACARS label to a ground system to be delivered to a peer groundapplication.

DRAWINGS

Embodiments of the present invention can be more easily understood andfurther advantages and uses thereof more readily apparent, whenconsidered in view of the description of the preferred embodiments andthe following figures in which:

FIG. 1 is a block diagram of one embodiment of a system with acommunications management unit (CMU) that is configurable to interfacewith a number of different computers on-board an aircraft, each of whichis configurable to run an Aircraft Operations Communication (AOC)application.

FIG. 2 is a flow chart of one embodiment of a method for processingdownlink messages from an Aircraft Operations Communication (AOC)application running on a communications management unit (CMU) or acomputer external to the CMU.

FIG. 3 is a flow chart of one embodiment of a method for processinguplink messages from a ground application that is destined for anAircraft Operations Communication (AOC) application running on eitherthe CMU or another computer on the aircraft.

In accordance with common practice, the various described features arenot drawn to scale but are drawn to emphasize features relevant to thepresent invention. Reference characters denote like elements throughoutfigures and text.

DETAILED DESCRIPTION

In the following detailed description, reference is made to theaccompanying drawings that form a part hereof, and in which is shown byway of specific illustrative embodiments in which the invention may bepracticed. These embodiments are described in sufficient detail toenable those skilled in the art to practice the invention, and it is tobe understood that other embodiments may be utilized and that logical,mechanical and electrical changes may be made without departing from thescope of the present invention. The following detailed description is,therefore, not to be taken in a limiting sense.

Embodiments of the present invention provide a process for handlingmessages for Aircraft Operations Communication (AOC) applications thatis independent of the computer running the AOC application on theaircraft. In embodiments of the invention, this is accomplished by afunction resident on the Communications Management Unit (CMU) that makesdownlink messages from AOC applications appear to have originated froman application running on the CMU even if the AOC application is runningon another computer on the aircraft. In one embodiment, the functionselects a label for the downlink message based on the message typerather than a label/sublabel that identifies the computer thatoriginated the message as would be standard operating procedure forAircraft Communications Addressing and Reporting System (ACARS)messages. Similarly, the function running on the CMU modifies uplinkmessages received for an AOC application running on a different computer(e.g., a computer other than the CMU), to include an indication of themessage type of the message so that the application running on the othercomputer may treat the message the same as if the AOC application wererunning on the CMU.

FIG. 1 is a block diagram of one embodiment of a system, indicatedgenerally at 100, with a communications management unit (CMU) 102 thatis configurable to interface with a number of different computers 104on-board an aircraft. Each of the computers 104 is configurable to runan Aircraft Operations Communication (AOC) application. The system 100uses, for example, the methods described below with respect to FIGS. 2and 3 to process downlink and uplink messages for AOC applicationsrunning on computers on the aircraft.

The CMU 102 includes an interface (I/F) 106 that provides a port forpassing messages between the CMU and the computers 104. In oneembodiment, the interface 106 is coupled to a communication bus 108,e.g., an ARINC 429 bus using an ARINC 619 protocol. The computers 104are also coupled to the communication bus 108. In some embodiments, thecomputers 104 include one or more of Electronic Flight bags (EFB) 110,Line Replaceable Units 112, and other computers 114, such as maintenanceterminals, PADs, personal devices, or cabin terminals. Each of thesecomputers is configurable to run one or more AOC applications orfunctions 116. These AOC functions are traditionally run on the CMU 102.Moving the AOC functions to the computers 104 can cause a problem withmessaging due to the standard way that messages from computers otherthan the CMU are handled when communicating with a ground system asdiscussed above.

To overcome this problem, the CMU 102 incorporates a message processingfunction or application 118 that, in one embodiment, implements theprocesses of FIGS. 2 and 3 for handling downlink and uplink messages,respectively. The CMU 102 communicates with a ground system 120 via anACARS router 122 and a communication circuit 124. The communicationcircuit 124 communicates with the ground system 120 over ACARScommunication links which can include VHF, HF, WiFi, cellular or SATCOMcommunication links. The ground system 120 includes one or more groundapplications 126 that each have a peer AOC application running on theCMU 102 or one of the computers 104.

The CMU 102 also interfaces and uses a user interface 128 and a display130 as is known to one of ordinary skill in the art.

In operation, the message processing application 118 processes uplinkand downlink messages for the AOC applications 116 whether they arerunning on the CMU 102 or one of the computers 104. If the AOCapplication 116 is running on one of the other computers 104, themessage processing application 118 handles downlink messages by using alabel associated with the message-type of the CMU downlink messagerather than the industry standard label/sublabel for a message for acomputer other than the CMU. In this way, the ground application 126will be able to handle the downlink message as if it were received froman AOC application 116 running on the CMU 102. Advantageously, themodification of downlink messages by the message processing application118 allows an operator to have messages handled appropriately by itsground application without having to track which configuration of AOCapplications is on each of the aircraft in its fleet. The processimplemented by the message processing application 118 makes the downlinkmessages all look like they come from AOC applications running on theCMU.

In the uplink, the message processing application 118 embeds anindication of the message type (derived from the label of the receiveduplink and optionally additional data from the uplink message like MFI,report code or other type identifier) into an uplink message that isdestined for an AOC application 116 running on one of the computers 104.This way, the AOC application 116 will know what type of message isbeing received and will thus be able to handle it accordingly. Again,the AOC applications 116 are able to process the uplink messagescorrectly whether running on the CMU or another computer due to theprocessing of the message processing application 118. The operator doesnot have to know the configuration of the aircraft receiving the messagefor it to be handled correctly.

Downlink and uplink messages for the AOC applications 116 running on theCMU 102 are handled using the normal protocol by message processingapplication 118.

FIG. 2 is a flow chart of one embodiment of a method, indicatedgenerally at 200, for processing downlink messages from an AircraftOperations Communication (AOC) application running on a communicationsmanagement unit (CMU) or a computer external to the CMU. The method 200begins at block 202 when a downlink message is received at the CMU froman AOC application. At block 204, the process determines whether thedownlink message is from an AOC application running on the CMU. If so,method 200 uses standard message processing (applying label) at block214.

If the downlink message is received from an AOC application running onanother computer, e.g., an electronic flight bag, line replaceable unit,maintenance terminal, PAD, personal device or cabin terminal or othercomputer on the aircraft, method 200 proceeds to block 206 anddetermines the message type. For example, the message type may bestandard messages to the airline operations center such as weatherupdates, free text messages, out, on, off and in. At block 208, method200 determines a label associated with the message type. For example,each of these messages has a standard label, e.g., weather relatedmessages may be designated with a label of “10,” free text messages maybe designated by the label “20” and out, on, off and in may bedesignated by labels 30, 31, 32, and 33, respectively. At block 210, thedownlink message is formatted with the determined label, e.g., the labelfield in the message header is modified and the message CRC is updatedrather than using the label/sublabel associated with the other computer.Finally, at block 212, method 200 sends the formatted message to thepeer ground application associated with the originating AOC applicationon the on-board computer.

FIG. 3 is a flow chart of one embodiment of a method, indicatedgenerally at 300, for processing uplink messages from a groundapplication that is destined for an Aircraft Operations Communication(AOC) application running on either the CMU or another computer on theaircraft. Method 300 begins at block 302 when an uplink message isreceived at the CMU from a ground application. The CMU reads themessage-type label at block 304. This message type label is in theheader of the message as is standard practice for ACARS messages.Advantageously, the ground application does not need to know thecomputer on the aircraft that is running the corresponding AOCapplication. The ground application simply uses the standard ACARSprotocol and labels the message as if the AOC application is running onthe CMU. Examples of the labels are the same as given above with respectto the downlink messages.

Once the message type has been determined, method 300 proceeds to block306 and determines the location of the destination application on theaircraft. For example, the destination AOC application could be on theCMU or it could be on any other appropriate computer, e.g., maintenanceterminal, PAD, personal device, cabin terminal, line replaceable unit orelectronic flight bag on-board the aircraft. At block 308, the processdetermines whether the location of the AOC application is on the CMU. Ifso, the process delivers the uplink message to the destinationapplication at block 312. If the destination AOC application is notrunning on the CMU, the method 300 continues to block 310 and updatesthe message with an indication of the type of message. For example, inone embodiment, the message type is written into the Message FunctionIndicator (MFI) field of the message. Alternatively, the message typemay be indicated using a pair of characters in the data field of themessage. This indication of the message type will allow the AOCapplication on the other computer to be able to identify the type ofmessage that is being received. The modified message is then deliveredto the destination AOC application at block 312.

The methods and techniques described here may be implemented in digitalelectronic circuitry, or with a programmable processor (for example, aspecial-purpose processor or a general-purpose processor such as acomputer) firmware, software, or in combinations of them. Apparatusembodying these techniques may include appropriate input and outputdevices, a programmable processor, and a storage medium tangiblyembodying program instructions for execution by the programmableprocessor. A process embodying these techniques may be performed by aprogrammable processor executing a program of instructions to performdesired functions by operating on input data and generating appropriateoutput. The techniques may advantageously be implemented in one or moreprograms that are executable on a programmable system including at leastone programmable processor coupled to receive data and instructionsfrom, and to transmit data and instructions to, a data storage system,at least one input device, and at least one output device. Generally, aprocessor will receive instructions and data from a read-only memoryand/or a random access memory. Storage devices suitable for tangiblyembodying computer program instructions and data include all forms ofnon-volatile memory, including by way of example semiconductor memorydevices, such as EPROM, EEPROM, and flash memory devices; magnetic diskssuch as internal hard disks and removable disks; magneto-optical disks;and DVD disks. Any of the foregoing may be supplemented by, orincorporated in, specially-designed application-specific integratedcircuits (ASICs) or Field Programmable Gate Arrays (FGPAs).

EXAMPLE EMBODIMENTS

Example 1 includes a method for processing Aircraft CommunicationsAddressing and Reporting System (ACARS) messages at a CommunicationsManagement Unit (CMU) on an aircraft, the method comprising: for anACARS downlink message: receiving a message at the CMU from anapplication on a computer external to the CMU onboard the aircraft;reading a field in the message that indicates a message type for thatapplication; determining an ACARS label associated with the messagetype; using the determined ACARS label instead of the industry standardACARS label/sublabel associated with the onboard application external tothe CMU; and sending the ACARS downlink message encoded with thedetermined ACARS label to a ground system to be delivered to a peerground application.

Example 2 includes the method of Example 1, wherein reading a fieldcomprises reading a message function indicator (MFI) field.

Example 3 includes the method of any of Examples 1-2, wherein reading afield comprises reading characters in selected positions in a data fieldof the message.

Example 4 includes the method of any of Examples 1-3, wherein receivinga message at the CMU from an application on a computer external to theCMU onboard the aircraft comprises receiving a message from one of anelectronic flight bag (EFB), line replaceable unit (LRU), maintenanceterminal, PAD, personal device or cabin terminal running an applicationthat is configured to communicate with a corresponding, peer groundapplication.

Example 5 includes the method of any of Examples 1-4, whereindetermining an ACARS label comprises determining the ACARS label thatwould be used with the message if the corresponding application wererunning on the CMU.

Example 6 includes the method of any of Examples 1-5, and furthercomprising, for an ACARS uplink message: receiving an ACARS message atthe CMU via a ground system from a ground application; reading an ACARSlabel of the ACARS message that indicates the message type; determiningwhether a destination application is resident in the CMU or othercomputer onboard the aircraft based on the message type; formatting theACARS uplink message based on the location of the destinationapplication: CMU or other computer on the aircraft; when the ACARSuplink message is intended for other computer on the aircraft, updatinga field indicating the message type in the formatted message; anddelivering the updated ACARS uplink message to the destinationapplication onboard the aircraft.

Example 7 includes the method of Example 6, wherein updating the fieldcomprises updating a message function indicator (MFI) field in theformatted message.

Example 8 includes the method of any of Examples 6-7, wherein updatingthe field comprises updating characters in selected positions in a datafield of the message.

Example 9 includes a communications management unit (CMU) for anaircraft, the CMU comprising: an interface to one or more computers; anAircraft Communications Addressing and Reporting System (ACARS) router;a communication circuit, coupled to the ACARS router, and configured tocommunicate ACARS messages with a ground system; a message processingapplication, wherein the message processing application is configured touse an ACARS label associated with a message type of a message receivedover the interface when downlinking messages via the ACARS router andthe communication circuit; and wherein the message processingapplication is configured to update a message type field in an uplinkmessage received from the communication circuit and the ACARS routerwhen the message is destined for a computer other than the CMU.

Example 10 includes the communication management unit of Example 9,wherein the interface comprises a bus that interfaces to one or more ofan electronic flight bag (EFB), line replaceable unit (LRU), maintenanceterminal, PAD, personal device, cabin terminal or other computer runningan AOC application.

Example 11 includes the communication management unit of any of Examples9-10, wherein the message processing application is configured to read amessage function indicator (MFI) field to determine the message type ofthe message received over the interface.

Example 12 includes the communication management unit of any of Examples9-11, wherein the message processing application is configured to readcharacters in selected positions in a data field of the message todetermine the message type of the message received over the interface.

Example 13 includes the communication management unit of any of Examples9-12, wherein the message processing application is configured todetermine the ACARS label that would be used with the message if thecorresponding application were running on the CMU.

Example 14 includes the communication management unit of any of Examples9-13, wherein the message processing application is configured to updatea message function indicator (MFI) field in the uplink message.

Example 15 includes the communication management unit of any of Examples9-14, wherein the message processing application is configured to updatecharacters in selected positions in a data field of the uplink message.

Example 16 includes a computer program product comprising programinstructions embodied on a non-transitory storage medium to processAircraft Communications Addressing and Reporting System (ACARS) messagesat a Communications Management Unit (CMU) on an aircraft, theinstructions being operable to cause a processor to: for an ACARSdownlink message: receive a message at the CMU from an application on acomputer external to the CMU onboard the aircraft; read a field in themessage that indicates a message type for that application; determine anACARS label associated with the message type; use the determined ACARSlabel instead of the industry standard ACARS label/sublabel associatedwith the onboard application external to the CMU; send the ACARSdownlink message encoded with the determined ACARS label to a groundsystem to be delivered to a peer ground application.

Example 17 includes the computer program product of Example 16, whereincausing the processor to receive a message at the CMU from anapplication on a computer external to the CMU onboard the aircraftcomprises causing the processor to receive a message from one of anelectronic flight bag (EFB), line replaceable unit (LRU), maintenanceterminal, PAD, personal device or cabin terminal running an applicationthat is configured to communicate with a corresponding, peer groundapplication.

Example 18 includes the computer program product of any of Examples16-17, wherein causing a processor to determine an ACARS label comprisescausing a processor to determine the ACARS label that would be used withthe message if the corresponding application were running on the CMU.

Example 19. The computer program product of any of Examples 16-18, andfurther comprising, for an ACARS uplink message, causing the processorto: receive an ACARS message at the CMU via a ground system from aground application; read an ACARS label of the ACARS message thatindicates the message type; determine whether a destination applicationis resident in the CMU or other computer onboard the aircraft based onthe message type; format the ACARS uplink message based on the locationof the destination application: CMU or other computer on the aircraft;when the ACARS uplink message is intended for other computer on theaircraft, update a field indicating the message type in the formattedmessage; and deliver the updated ACARS uplink message to the destinationapplication onboard the aircraft.

Example 20 includes the computer program product of Example 19, whereincausing the processor to update the field comprises causing theprocessor to update one of (1) a message function indicator (MFI) fieldor (2) characters in selected positions in a data field of the formattedmessage.

Although specific embodiments have been illustrated and describedherein, it will be appreciated by those of ordinary skill in the artthat any arrangement, which is calculated to achieve the same purpose,may be substituted for the specific embodiment shown. This applicationis intended to cover any adaptations or variations of the presentinvention. Therefore, it is manifestly intended that this invention belimited only by the claims and the equivalents thereof.

What is claimed is:
 1. A method for processing Aircraft CommunicationsAddressing and Reporting System (ACARS) downlink and uplink messages ata Communications Management Unit (CMU) on an aircraft independent of acomputer running Aircraft Operations Communication (AOC) applications,the method comprising: for the ACARS downlink message: receiving theACARS downlink message at a message processing application executing onthe CMU from the AOC application on the computer external to the CMUonboard the aircraft; reading, by the message processing application, afield in the ACARS downlink message that indicates a message type forthe application which originated the ACARS downlink message;determining, by the message processing application, an ACARS labelassociated with the message type, wherein the determined ACARS label isone of a predetermined standard label designated for a message type foreach type of AOC applications running on one or more external computersto the CMU; using the determined ACARS label instead of an industrystandard ACARS label/sublabel associated with the AOC applicationexternal to the CMU, wherein the determined ACARS label makes the ACARSdownlink message appear to have originated at the CMU; and sending, bythe message processing application, the ACARS downlink message modifiedwith the determined ACARS label to a ground system to be delivered to anappropriate peer ground application without having to track whichconfiguration of AOC applications is on each of the aircraft, whereinthe industry standard ACARS label/sublabel identifies a computer thatoriginated the ACARS downlink message rather than the AOC applicationthat originated the ACARS downlink message and the predeterminedstandard labels identifies a type of the AOC application that originatedthe ACARS downlink message.
 2. The method of claim 1, wherein reading afield comprises reading a message function indicator (MFI) field.
 3. Themethod of claim 1, wherein reading a field comprises reading charactersin selected positions in a data field of the ACARS downlink message. 4.The method of claim 1, wherein receiving the ACARS downlink message atthe CMU from the AOC application on the computer external to the CMUonboard the aircraft comprises receiving the ACARS downlink message fromone of an electronic flight bag (EFB), line replaceable unit (LRU),maintenance terminal, PAD, personal device or cabin terminal running anapplication that is configured to communicate with a corresponding, peerground application.
 5. The method of claim 1, wherein determining anACARS label comprises determining the ACARS label that would be usedwith the ACARS downlink message if the corresponding AOC applicationwere running on the CMU.
 6. The method of claim 1, and furthercomprising, for the ACARS uplink message: receiving the ACARS uplinkmessage at the CMU via a ground system from a ground application;reading an ACARS label of the ACARS uplink message that indicates themessage type; determining whether a destination application is residentin the CMU or other computer onboard the aircraft based on the messagetype; formatting the ACARS uplink message based on the location of thedestination application: CMU or other computer on the aircraft; when theACARS uplink message is intended for other computer on the aircraft,updating a field indicating the message type in the formatted ACARSuplink message; and delivering the updated ACARS uplink message to thedestination application onboard the aircraft.
 7. The method of claim 6,wherein updating the field comprises updating a message functionindicator (MFI) field in the formatted ACARS uplink message.
 8. Themethod of claim 6, wherein updating the field comprises updatingcharacters in selected positions in a data field of the ACARS uplinkmessage.
 9. A communications management unit (CMU) for an aircraft, theCMU comprising: an interface to one or more computers external to theCMU onboard the aircraft; an Aircraft Communications Addressing andReporting System (ACARS) router; a communication circuit, coupled to theACARS router, and configured to communicate ACARS downlink and uplinkmessages with a ground system; a message processing applicationexecuting on the CMU independent of the one or more computer runningAircraft Operations Communication (AOC) applications, wherein themessage processing application is configured to use a determined ACARSlabel associated with a message type of a received ACARS downlinkmessage instead of an industry standard ACARS label/sublabel associatedwith the AOC application external to the CMU, wherein the determinedACARS label is one of a predetermined standard label designated for amessage type for each type of AOC applications running on one or moreexternal computers to the CMU, wherein the determined ACARS label makesthe ACARS downlink message appear to have originated at the CMU, theACARS downlink message received over the interface when downlinkingmessages via the ACARS router and the communication circuit to a groundsystem to be delivered to an appropriate peer ground application withouthaving to track which configuration of AOC applications is on each ofthe aircraft, wherein the industry standard ACARS label/sublabelidentifies a computer that originated the ACARS downlink message ratherthan the AOC application that originated the ACARS downlink message andthe predetermined standard labels identifies a type of the AOCapplication that originated the ACARS downlink message; and wherein themessage processing application is configured to update a message typefield in an ACARS uplink message received from the communication circuitand the ACARS router when the ACARS uplink message is destined for oneof the one or more computers other than the CMU.
 10. The communicationmanagement unit of claim 9, wherein the interface comprises a bus thatinterfaces to one or more of an electronic flight bag (EFB), linereplaceable unit (LRU), maintenance terminal, PAD, personal device,cabin terminal or other computer running an AOC application.
 11. Thecommunication management unit of claim 9, wherein the message processingapplication is configured to read a message function indicator (MFI)field to determine the message type of the ACARS downlink messagereceived over the interface.
 12. The communication management unit ofclaim 9, wherein the message processing application is configured toread characters in selected positions in a data field of the ACARSdownlink message to determine the message type of the ACARS downlinkmessage received over the interface.
 13. The communication managementunit of claim 9, wherein the message processing application isconfigured to determine the ACARS label that would be used with theACARS downlink message if the corresponding AOC application were runningon the CMU.
 14. The communication management unit of claim 9, whereinthe message processing application is configured to update a messagefunction indicator (MFI) field in the ACARS uplink message.
 15. Thecommunication management unit of claim 9, wherein the message processingapplication is configured to update characters in selected positions ina data field of the ACARS uplink message.
 16. A computer program productcomprising program instructions embodied on a non-transitory storagemedium to process Aircraft Communications Addressing and ReportingSystem (ACARS) downlink and uplink messages at a CommunicationsManagement Unit (CMU) on an aircraft independent of a computer runningAircraft Operations Communication (AOC) applications, the instructionsbeing operable to cause a processor to: for the ACARS downlink message:receive the ACARS downlink message at a message processing applicationexecuting on the CMU from the AOC application on the computer externalto the CMU onboard the aircraft; read, by the message processingapplication, a field in the ACARS downlink message that indicates amessage type for the application which originated the ACARS downlinkmessage; determine, by the message processing application, an ACARSlabel associated with the message type, wherein the determined ACARSlabel is one of a predetermined standard label designated for a messagetype for each type of AOC applications running on one or more externalcomputers to the CMU; use the determined ACARS label instead of anindustry standard ACARS label/sublabel associated with the AOCapplication external to the CMU, wherein the determined ACARS labelmakes the ACARS downlink message appear to have originated at the CMU;send, by the message processing application, the ACARS downlink messagemodified with the determined ACARS label to a ground system to bedelivered to an appropriate peer ground application without having totrack which configuration of AOC applications is on each of theaircraft, wherein the industry standard ACARS label/sublabel identifiesa computer that originated the ACARS downlink message rather than theAOC application that originated the ACARS downlink message and thepredetermined standard labels identifies a type of the AOC applicationthat originated the ACARS downlink message.
 17. The computer programproduct of claim 16, wherein causing the processor to receive the ACARSdownlink message at the CMU from the AOC application on the computerexternal to the CMU onboard the aircraft comprises causing the processorto receive the ACARS downlink message from one of an electronic flightbag (EFB), line replaceable unit (LRU), maintenance terminal, PAD,personal device or cabin terminal running an application that isconfigured to communicate with a corresponding, peer ground application.18. The computer program product of claim 16, wherein causing aprocessor to determine an ACARS label comprises causing a processor todetermine the ACARS label that would be used with the ACARS downlinkmessage if the corresponding AOC application were running on the CMU.19. The computer program product of claim 16, and further comprising,for the ACARS uplink message, causing the processor to: receive theACARS uplink message at the CMU via a ground system from a groundapplication; read an ACARS label of the ACARS uplink message thatindicates the message type; determine whether a destination applicationis resident in the CMU or other computer onboard the aircraft based onthe message type; format the ACARS uplink message based on the locationof the destination application: CMU or other computer on the aircraft;when the ACARS uplink message is intended for other computer on theaircraft, update a field indicating the message type in the formattedACARS uplink message; and deliver the updated ACARS uplink message tothe destination application onboard the aircraft.
 20. The computerprogram product of claim 19, wherein causing the processor to update thefield comprises causing the processor to update one of (1) a messagefunction indicator (MFI) field or (2) characters in selected positionsin a data field of the formatted ACARS uplink message.